Dyestuffs of the safranine series and the process of making them



Patented Sept. 20, 1932 UNITED :SVJTATEVQS: PATENT WILHELM NEELMEIER AND mneoiios NocKEn; or LEVERKUSEN-ON-THE-RHI1\TE,.GER

MANY,ASSIGNORS T0 GENERAL ANILINE WORKS,"I1\TC., OF NEW YORK, 1v. Y.,'A con- PORATION OF DELAWARE DYES'IUFFS OF THE SAFRANTNE SERIES AND THE PROCESS OF MAKING THEM' No Drawing. Application filed October 29, 1928, Serial No.'315-,920, and in Germany November 7, 1927.

The present invention relates to. new dyestuffs of the safranine series and to a process of preparing them, more particularly it relates to dyestuffs having in'form of their salts with mineral acids the probable general formula:

N ineral acid radical R1 J II N R5 wherein it represents asubstituent of the The new dyestuffs of the above given pro-bable formula are obtainable by oxidizing together a compound of the general formula:

"wherein R and R stand for a substituent.

of the group consisting of hydrogen, alkyl and aryl, and wherein the nucleus marked as I may be further substituted but one"ortho-' position to theNI-I' group is unoccupied with a compound of the general formula':'

oxidizing agent further substituted but the position y in the nucleus II is unoccupied.

The oxidation process may be performed according to one of the methods used in the manufacture of safranine dyestuffs, for instance, while uslng as oxidizing agents b1- chromates in acetic acidor dilute mineralic acid solution, or potassium ferricyanide or'in some cases even air in alkaline solution. The temperatures during the process may vary within wide limits depending on the oxidiz ing agent as well as on the starting materials used. V

The oxidation probably takes place in two stages at first compounds of the probable formula W mineral acidradical I 11 R1 N u N R3 I R R4 I above given signification) and wherein the position y in the nucleus I is unoccupied, and then the safranines themselves being formed. l/Vhen oxidizing in an acid medium it will often be of advantage to neutralize the acid after the first step of the reaction, for in stance,-by the addition of calcium-carbonate,

and thereuponadding'new quantities of an for performing the second step. b

caries f The shadesof ournew dyestuffs can be improved in many cases byboilingthe dyestuffs with diluted sulfuric acid orwith an.

aqueous solution of an alkali metal. carbonate, or by treating them with a reducing agent,

such as zinc in'diluted'acetic acid, sodium.

7 hydrosulfite in. alkaline solution, and the like i and re-oxidiz'ing the leucocompounds. thus formed, for instance, with a current of air.

The dyestuffs thus obtainable are in form of their salts with mineral acids dark powders with a bronze lustre, soluble in water with violet to greenish-blue colorations, soluble in 'sulfuric acid with a green tint and dyeing wool from an acid bath intense redmium hydroxide, 20 ccs. of sulfuric acid of 20% strength are added per litre ofliquidand the mixture is boiled for about one hour.

dish violet to greenishblue shades. These. dyeings combine a satisfactory capacity for even dyeing with good fastness to light, fulling and steaming. The dyestuffs having in form of their salts with mineral acids the probable formula:

f Lt,

amine-2-sulfonic acid and with 294 parts by weight of e-amino-4-methoxy-diphenylamine-2-sulfonic acid are dissolved in 10000 parts of water while adding the requisite quantity of caustic soda to form a neutral solution. The solution is-heated to 50 C. and treated for about one hour with about 2000 parts by weight ofan 20% aqueous sodium bichromate solution with which 700 parts by weight of glacial acetic acid have been mixed. Thereupon 700 parts by weight of calcium carbonate are added and a further quantity of about 2000.. parts by weight of an aqueous sodium bichromate solution of 20% strength is causedto run in. After stirring for about five hours at about 50 C. the resulting product is'filtered and boiled with water. The filtrate is freed from chro- The dyestufi cyrstallizes out on cooling. It is purified by crystallization from a weak alkaline sodium carbonate solution with the addition of sodi'umchloride. The dyestufl thus'obtained is in form of its salts with min-l eral acids a dark crystalline powder with a bronze lustre. Itdissolves in water with 7 a violet coloration, in concentratedv sulfuric acid with a green coloration and dyes wool.

to fulling and very fast to light. The product probably corresponds in form of its salts with mineral acids to the formula:

The t 'ac'etamino ii amino-4'-methyldipher N I mineral acidradical 7 I r I RI NH \F nylamine-2-sulfonicacid used as. starting material obtainable by condensing- 4- nitro-chlorobenzene-2-sulfonic' acid with 4- methyll.3 phe'nylenediamine, reducing v the nitro group 'andacetylating the aminogroup.

It is a colorless crystalline powder, which. 0'

turns bluish .while keeping it in the airand which is readily soluble in dilute alkalies.

Example 2.When replacing the 4amino* 4E- methoxy diphenylamine 2 sulfonic' acid used in Example 1 by244'parts by weight of d -amino-diethylaniline-Ei-sulfonic acid a dyestuff is obtained, whichjdyes wool from an acid bath a clear reddish violet. The oxidation in this case is advantageously carried out at a temperature of between 0 to about 5 C.

Example 3.26i parts by weight of 4- amino-diphenylamine-2-sulfonic acidare oxidized as described inExample 2, together with 337 parts by weight of 't-nitro-3 dimethylamino-diphenylami'ne-2-sulfonic acid. The 'dyestuff obtained is a dark crystalline powder with a bronze lustre. It dissolves in water with a reddish blue coloration, in concentratedsulfuric acid with a green coloration and dyes wool from an acid bath a fast reddish blue.

The nitro group of the dyestufi' can be replaced by the amino group by treating the dyestufi with a reducing agent, for examp e with zinc dust in acetic acid solution or with hydrosulfite in alkaline; solution and oxidizing the thus formed leuco compound;

When using instead of -amino-diphenylamine2rsulfonic acid, 4-ainin'o-U-methoxydiphenylainine-2-sulfonic acid a similar dyestuif is obtained, dyeing Woolblue shades very fast to light.

The 4 nitro 3- dimethylamino-diphenylamine-2-sulfonic acid can be obtained by condensing sodium nitrochlorobcnzene sulfonate with 3ainino-dimethylaniline. It is a brownish powder, readily soluble in dilute alkalies. 4

We claim: I V

1. The process which comprises oxidizing $5 from an acid bath an even'violetshade fast'together a compound of the general formula:

wherein R and R stand for a substituent of the group consisting of hydrogen, alkyl and aryl, wherein one of the ortho-positions to the NH group is unoccupied, and wherein the nucleus marked as I may be substituted by a substitu-ent of the group consisting of halogen, alkyl or the sulfonic acid group with a compound of the general formula:

' wherein the position 7 is unoccupied, wherein stands for a substituent of the group consisting of NH NO and NH-aoidyl, and wherein the benzene nucleus marked as II may be substituted by a substituent of the group consisting of halogen, alkyl and the sulfonic acid group.

2. The process which comprises treating a neutral aqueous solution of 335 parts by weight of l-acetamino-ii'-amino-4-methyl-diphenylamine-2-sulfonic acid and 294 parts by u 'eight of 4-aminoi-methoXy-diphenylamine-2-sulfonic acid for about one hour with about 2000 parts by weight of an aqueous sodium-bichromate solution of strength to which glacial acetic acid has been added,

wherein m represents a substituent of the group consisting of NIL, NO and NI-I-aci dyl; R R R and R stand for substituents of the group consisting of hydrogen, alkyl and aryl, and wherein the nuclei marked as I and II may be substituted by substituents of the group consisting of halogen, alkyl and the sulfonic acid group, said products being in form of their salts with mineral acids dark powders with a bronze lustre soluble inwater with violet to greenish-blue colorations, dyeing wool from an acid bath intense reddish violet to greenish-blue shades.

4. The new products having in form of their salts with mineral acids the probable formula;

N mineral acid a radical R. 0 EN -N M /V R4 soar! wherein w represents a substituent of the group consisting of NI-I N0 and NI-I- acidyl,

R, R and R stand for substituents of the group consisting of hydrogen, alkyl and aryl, and wherein the nuclei marked as I and II may be substituted by substituents of the group consisting of halogen, alkyl and the sulfonic acid group, said products being in form of their salts with mineral acids dark powders with a bronze lustre, soluble in water with violet to greenish-blue colorations, dyeing wool from an acid bath intense reddish violet to greenish-blue shades of an cs 'pecially good fastness to light. 7

5. The product having in form of its salts with mineral acids the probable formula:

N\ CH3 HO S- mineral I acid N 1glr'adieal 2 H 0 NH \N/ SOaH said product being in form of its salts with mineral acids a dark powder with a bronze lustre, dyeing wool from an acid bath a violet shade, fast to fulling and light. I

In testimony whereof we have hereunto set our hands.

WILHELM NEELMEIER; THEODOR NOCKEN. 

